49ers activate Michael Crabtree

SANTA CLARA -- Michael Crabtree officially was activated Tuesday off the physically-unable-to-perform list. The 49ers cleared room for him on the 53-man roster by releasing No. 3 quarterback McLeod Bethel-Thompson.

The question of whether Crabtree is fully healed from the May 21 tear of his right Achilles might be answered as soon as Sunday's game against St. Louis.

Adding a productive receiver of Crabtree's caliber, especially on the outside, is "another dimension that we need," wideout Anquan Boldin said after Monday's victory in Washington. The 49ers still are averaging a league-worst 173.5 passing yards per game, despite Colin Kaepernick's 235-yard, three-touchdown effort Monday that resulted in a career-best 134.5 passer rating.

Crabtree caught a career-high 85 passes for 1,105 yards and nine touchdowns last season, and his chemistry with Kaepernick came on strong late in the year and playoffs.

Crabtree caught five of Colin Kaepernick's 10 touchdown passes last regular season, and three of four in the playoffs. All 14 of Kaepernick's touchdown passes this season have gone to tight end Vernon Davis (nine) and Boldin (five).

Other than confirming he's doing well, Crabtree didn't want to talk after Monday's game about his health status or potential availability against the Rams.

Crabtree is the latest in a line of recent reinforcements, including wide receiver Mario Manningham, cornerback Eric Wright, linebackers Aldon Smith and Nick Moody, nose tackle Quinton Dial and defensive tackle Tank Carradine, who hasn't debuted in a game yet.

"We need them all," coach Jim Harbaugh said. "Where our team is headed, it's only for the tough."

Linebacker Ahmad Brooks got a good, close look at Washington's Robert Griffin III on Monday night, delivering two of the 49ers' four sacks of the Redskins quarterback.

So Brooks might know what he's talking about when he offers this assessment of the 2012 offensive rookie of the year, via Comcast SportsNet: "He's obviously a man and he makes his own decisions, but I personally don't feel he should be playing right now."

Griffin has been playing on a repaired right knee after ligament damage in a playoff loss back January. When asked, Brooks confirmed that is the reason he feels RG3 doesn't belong on the field at this point.

"I don't think he should be playing," he said. "You can see it. Everybody can see it, everybody can see it."